Radiation curable siloxane compositions containing vinyl ether functionality and methods for their preparation

Abstract: The present invention relates to radiation curable silicone vinyl ethers and methods for their preparation and use. Silicone vinyl ethers are curable by addition of photocleavable acids and exposure to ultraviolet light or electron beam radiation.

Description: The present invention relates to compositions containing vinyl ether functional silicones and to their preparation and to their use. Silicone vinyl ethers are curable by addition of photocleavable acids and exposure to actinic radiation. Alkenyl ether functional organosilicon compounds have been described in the art. For example, U.S. Patent No. 4,617,238 discloses a photopolymerizable composition wherein only one vinyl ether group for each SiH group is incorporated into the siloxane molecule at any given time. Other alkenyloxy functional organosilicon compounds are described in U.S. Patent Nos. 4,707,503; 5,057,549; 5,039,176 and EP Patent No. 0 462 389. The above methods rely on competition between the vinyl ether group and other alkenyl groups within the same compound and do not result in quantitative conversion of SiH to vinyl ether. In contrast, the method of the present invention yields quantitative conversion of siloxanes to vinyl ether, a preferred radiation sensitive group. The present invention provides a method for making vinyl ether functional siloxane, the method comprising the steps of: (I) reacting (a) a silane having the formula R x Si(OR 1 ) 4-x ; (b) water; and (c) an acidic condensation catalyst, wherein R is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent alkyl radical having from 1 to 8 carbon atoms, x has a value of from 0 to 3, with the proviso that the molar ratio of water to alkoxy radicals is less than 0.5; (II) removing alcohol from the mixture of step (I); (III) neutralizing the mixture of step (II); (IV) adding a vinyl ether compound having the formula HOR 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms to the mixture of step (III); (V) adding a transesterification catalyst to the mixture of step (IV); and (VI) removing volatiles from the mixture of step (V). An alternative method of making a vinyl ether functional siloxane comprises the steps of: (I) reacting in the presence of a non-acidic equilibration catalyst (a) a cyclic compound having the formula and (b) a compound having the formula HOR 1 OCH=CH 2 , wherein R is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms and x has a value of from 3 to 10; (II) removing volatiles from the mixture of step (I); and (III) neutralizing the mixture of step (II). The present invention further relates to vinyl ether functional polysiloxane compounds. The present invention also relates to a curable composition comprising the vinyl ether functional polysiloxane compound above in combination with a photocleavable acid. This invention also provides a method of making a curable composition, the method comprising the steps of (I) applying the curable composition to a solid substrate to form a coating; and (II) exposing the coating to an energy source selected from (i) actinic radiation and (ii) actinic radiation in combination with heat in an amount sufficient to cure the coating. It is an object of the present invention to provide a method of preparing ultraviolet (UV) or electron beam (EB) curable organopolysiloxanes suitable for pressure sensitive adhesive release applications. It is also an object of the present invention to produce silicone vinyl ether copolymers or oligomers which are curable by addition of photocleavable acids and exposure to UV or EB radiation. It is a further object of this invention to provide UV- curable silicone compositions which may be catalyzed by a variety of curing catalysts at especially rapid cure rates. Step (I) in this method comprises reacting a silane having the formula R x Si(OR 1 ) 4-x with water and an acidic condensation catalyst. R is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent alkyl radical having from 1 to 8 carbon atoms and x has a value from 0 to 3. It is also required in this invention that the molar ratio of water to alkoxy radicals is less than 0.5. The preferred molar ratio is 0.1 to 0.4. Monovalent hydrocarbon radicals include alkyl radicals, such as methyl, ethyl, propyl, butyl, hexyl and octyl; cycloaliphatic radicals, such as cyclohexyl; aryl radicals, such as phenyl, tolyl and xylyl; aralkyl radicals, such as benzyl and phenylethyl; and olefinic hydrocarbon radicals, such as vinyl, allyl, methallyl, butenyl and hexenyl, octenyl, cyclohexenyl and styryl. Alkenyl radicals are preferably terminally unsaturated. Highly preferred monovalent hydrocarbon radical for this invention are methyl, phenyl, vinyl and 5-hexenyl. Monovalent halohydrocarbon radicals free of aliphatic unsaturation include any monovalent hydrocarbon radical noted above which has at least one of its hydrogen atoms replaced with a halogen, such as fluorine, chlorine or bromine. Preferred monovalent halohydrocarbon radicals have the formula C n F 2n+1 CH 2 CH 2 - wherein the subscript n has a value of from 1 to 8, such as, CF 3 CH 2 CH 2 - and C 4 F 9 CH 2 CH 2 -. The R radicals can be identical or different. R 1 is a monovalent alkyl radical having from 1 to 8 carbon atoms which includes methyl, ethyl, propyl, butyl, hexyl and octyl. The amount of silane employed in the present invention varies depending on the amount of water and condensation catalyst employed. It is preferred that from 50 to 99 weight percent of silane be used, and it is highly preferred that from 85 to 95 weight percent be employed, said weight percent being based on the total weight of the composition. Water is also included in the mixture of step (I), preferably clear water and, most preferably, distilled and/or deionized water. It is preferred that from 1 to 50 weight percent of water be used, and it is highly preferred that from 5 to 15 weight percent be employed, said weight percent being based on the total weight of the composition. The acidic condensation catalysts suitable for use in Step (I) include condensation catalysts having a pH of less than 7. Examples include hydrochloric acid (HCl), H 2 SO 4 , sulfonic acids, H 3 PO 4 , (PNCl 2 ) x , acid anhydrides, acid clays, ion exchange resins, RCOCl and (RCO) 2 O, wherein R is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, such as methyl. It is preferred that the condensation catalyst is selected from hydrochloric acid, H 2 SO 4 and sulfonic acids. The amount of acidic condensation catalyst needed for our method will be determined by the skilled artisan through routine experimentation. Typically, this component is employed at a level of 0.1 to 5 weight percent, preferably 0.1 to 1 weight percent, said weight percent being based on the total weight of the composition. Step (II) in our method comprises removing alcohol from the reaction mixture of step (I). Methods of removing volatile components are well known in the art and need no extensive delineation herein. Methods of removing volatile components are exemplified by heating, application of a vacuum, molecular stills, rotoevaporators and wipe film evaporators, with the preferred method being wipe film evaporators. It is preferred that the alcohol in Step (I) be removed by heating the mixture to a temperature above 80°C. Step (III) comprises neutralizing the mixture of step (II). Neutralization of acidic mixtures is well known in the art and needs no extensive delineation herein. It is preferred that the mixture of step (II) be neutralized by adding a basic compound to it such as sodium bicarbonate (NaHCO 3 ), calcium carbonate (CaCO 3 ), Na 2 CO 3 , (NH 4 ) 2 CO 3 , CO 2 , H 2 O and a filter aid such as diatomaceous earth. Step (IV) of the present invention comprises adding a vinyl ether compound having the formula HOR 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms to the neutralized mixture of step (III). R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms. Divalent hydrocarbon radicals suitable as R 2 are alkylene radicals, such as methylene, ethylene, trimethylene, 2-methyltrimethylene, pentamethylene, hexamethylene, 3-ethylhexamethylene, octamethylene, -CH 2 (CH 3 )CH-, -(CH2) 4 -, -CH 2 CH(CH 3 )CH 2 - and -(CH 2 ) 18 -; cycloalkylene radicals such as cyclohexylene; arylene radicals such as phenylene and combinations of divalent hydrocarbon radicals such as benzylene, i.e., -C 6 H 4 CH 2 -. Examples of suitable divalent halohydrocarbon radicals include any divalent hydrocarbon radical wherein one or more hydrogen atoms have been replaced by halogen, such as fluorine, chlorine or bromine. Preferably divalent halohydrocarbon radicals have the formula -CH 2 CH 2 C n F 2n CH 2 CH 2 - wherein n has a value of from 1 to 10 such as -CH 2 CH 2 CF 2 CF 2 CH 2 CH 2 -. Preferably, R 2 is an alkylene radical having from 1 to 8 carbon atoms such as methylene, ethylene, propylene, butylene, hexylene and cyclohexyldimethylene. The amount of vinyl ether compound employed in the present invention varies depending on the amount of silane, water and condensation catalyst employed. It is preferred that from 5 to 90 weight percent of vinyl ether be used and it is highly preferred that from 15 to 50 weight percent be employed, said weight percent being based on the total weight of the composition. Step (V) of the present invention comprises adding a transesterification catalyst to the mixture of step (IV). Suitable catalysts have been described in U.S. Patent No. 3,133,111 and have been described in other publications. They include alkali metal alkoxides, Sn compounds, Ti compounds, Ba compounds, as well as standard strong alkali compounds. Strong acid compounds are to be avoided as they tend to polymerize oxyalkenyl groups. Examples of suitable transesterification catalysts include dimethyltin neodecanoate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, zinc napthenate, cobalt napthenate, zinc octylate, tin octylate, cobalt octylate, diisooctyl mercaptoacetate, zirconium napthenate, zirconium octylate, tetrabutyl orthotitanate, tetraisopropyl titanate, barium hydroxide monohydrate, stannous octoate and other organic metal catalysts. It is preferred that the catalyst be selected from alkali metal alkoxides such as tetraisopropyl titanate, barium hydroxide monohydrate and sodium methoxide. The amount of catalyst needed will be determined by the skilled artisan through routine experimentation. Typically, it is employed at a level of 0.1 to 5 weight percent, preferably 0.1 to 3 weight percent, said weight percent being based on the total weight of the composition. Step (VI) in the method of this invention comprises removing volatiles from the mixture of Step (V). Methods of removing volatile components are well known in the art and need no extensive delineation herein. Any method of removing volatile components can be used, such as molecular stills, rotoevaporators and wipe film evaporators, with the preferred method being wipe film evaporators. The method of the present invention can further comprise heating the mixture after step (I). By heat, it is meant infrared radiation, hot-air or microwave radiation. It is preferred that the mixture resulting from Step (I) be heated from room temperature to a temperature of less than 150°C., and it is highly preferred that this mixture be heated at a temperature of from 50 to 85°C. The method of the present invention can further comprise adding a polydiorganosiloxane. Preferably, this compound has the formula HOSiR 3 2 O(R 3 2 SiO) n SiR 3 2 OH wherein R 3 is selected from a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms and hydrogen atom and n has a value from 0 to 15,000. Suitable monovalent hydrocarbon and halohydrocarbon radicals as R 3 are delineated above for R in Step (I). It is preferable that the polyorganosiloxane be added prior to Step (IV). In a preferred embodiment of the present invention, the polydiorganosiloxane is a hydroxyl-endblocked polydimethylsiloxane having the formula HOMe 2 SiO(Me 2 SiO) n SiMe 2 OH wherein n has a value of from 10 to 60. The polyorganosiloxanes are well known in the silicone art and need no detailed delineation herein. Suitable polydiorganosiloxanes are disclosed in U.S. Patent Nos. 2,807,601; 2,985,545; 3,900,617; 4,190,688; 4,293,671; 4,476,241; 4,559,396; 4,562,096; 4,587,136 and 4,609,574. It is preferable that 10 to 80 weight percent of hydroxylendblocked polydiorganosiloxane be employed in this invention. It is highly preferred that 25 to 50 weight percent of hydroxyl-endblocked polydiorganosiloxane be employed, said weight percent being based on the total weight of the composition. The method of our invention can further comprise adding an alcohol having the formula R 4 OH, wherein R 4 is is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms. Monovalent hydrocarbon and halohydrocarbon radicals suitable as R 4 in the invention are delineated above for R in Step (I). It is preferred that the alcohol be added after step (I). It is preferable that 1 to 50 weight percent of alcohol be used in the instant method, and it is highly preferred that 10 to 30 weight percent of alcohol be used, said weight percent being based on the total weight of the composition. The present invention also relates to an additional method of making a vinyl ether functional siloxane, the method comprising the steps of: (I) reacting in the presence of a non-acidic equilibration catalyst (a) a cyclic compound having the formula and (b) a compound having the formula HOR 6 OCH=CH 2 wherein R 5 is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 6 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms and y has a value of from 3 to 10, (II) removing volatiles from the mixture of (I); and (III) neutralizing the mixture of (II). Step (I) in this additional method of the invention comprises reacting the compounds (a) and (b) above in the presence of a non-acidic equilibration catalyst. The monovalent hydrocarbon and halohydrocarbon radicals of R 5 are delineated above in the other methods of this invention including amounts and preferred embodiments thereof. The divalent hydrocarbon or halohydrocarbon radicals of R 6 are as delineated above including amounts and preferred embodiments thereof. Suitable non-acidic equilibration catalysts include catalysts such as heat, amine carboxylates, heavy metal carboxylates and isocyanates. Also included are silanolates, phenoxides, mercaptides, CaO, BaO, LiOH, BuLi, amines, potassium hydroxides, cesium hydroxides, ammonium hydroxides and phosphorus hydroxides. It is preferred that the non-acidic equilibration catalyst is selected from silanolates and ammonium hydroxides. It is most preferred that the silanolates are selected from potassium silanolates and sodium silanolates. The amount of catalyst needed will be determined by the skilled artisan through routine experimentation. Typically, this component is employed at a level of 0.1 to 5 weight percent, preferably 0.1 to 3 weight percent, said weight percent being based on the total weight of the composition. Step (II) in this method of the invention comprises removing volatiles from the mixture of step (I). Methods of removing volatile components are as delineated in the methods above including preferred methods thereof. Step (III) in the additional method comprises neutralizing the mixture of step (II) as delineated above including preferred methods thereof. It is preferred, however, that the mixture of step (III) be neutralized by adding carbon dioxide or acetic acid followed by filtration to remove salt by-products. This additional method of this invention can further comprise heating the mixture after step (I). Heating can be as delineated above including preferred temperatures and methods of applying heat. The additional method of our invention can further comprise adding a hydroxyl-endblocked polydiorganosiloxane prior to step (III) as delineated above including amounts and preferred embodiments thereof. The additional method of this invention can further comprise adding a silane having the formula R 7 c Si(OR 8 ) 4-c prior to Step (III). R 7 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 8 is a monovalent alkyl radical having from 1 to 8 carbon atoms and c has a value from 0 to 3. The silane is as delineated above for silanes in the other methods of this invention including amounts and preferred embodiments thereof. The present invention further relates to a random siloxane copolymer composition having the general formula: wherein R is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 8 carbon atoms or is a compound having the formula R 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, w has a mole percent of from greater than 0 to 100, x has a mole percent of from 0 to less than 100, y has a mole percent of from 0 to less than 100, z has a mole percent of from 0 to less than 100, a is an integer of from 0 to 3, b is an integer of from 0 to 2, the sum of w+x+y+z being equal to 100 mole percent, with the proviso that at least one R 2 OCH=CH 2 group exists in each molecule. This siloxane copolymer is comprised of siloxane units of the formula siloxane units of the formula siloxane units of the formula (RSiO 3/2 ) y , and siloxane units of the formula (SiO 2 ) z with the molar ratios defined in the formula hereinabove. The monovalent hydrocarbon and halohydrocarbon radicals and the divalent hydrocarbon or halohydrocarbon radicals in the siloxane polymer of the instant invention are as delineated above including preferred embodiments thereof. It is preferred in the instant invention that w has a mole percent of from 5 to 90, x has a mole percent of from 0 to 75, y has a mole percent of from 0 to 40 and z has a mole percent of from 0 to 10. It is further preferred that the molecular weight of said composition be controlled to deliver a solvent-free viscosity of from 20 to 2000 mPa·s (centipoise) at 22°C. The present invention is further directed to a curable coating composition comprising (A) the siloxane copolymer delineated above and (B) a photocleavable acid. Suitable photocleavable acids include onium salts and certain nitrobenzyl sulfonate esters. Preferred are onium salts having the formulae R 2 I + MX n - , R 3 S + MX n - , R 3 Se + MX n - , R 4 P + MX n - and R 4 N + MX n - , wherein R is the same or different organic radicals having from 1 to 30 carbon atoms, including aromatic carbocyclic radicals of from 6 to 20 carbon atoms that are substituted with from 1 to 4 monovalent hydrocarbon radicals selected from alkoxy radicals having from 1 to 8 carbon atoms, alkyl radicals having from 1 to 8 carbon atoms, nitro, chloro, bromo, cyano, carboxy, mercapto and aromatic heterocyclic radicals including pyridyl, thiophenyl and pyranyl. The symbol M in the above formulae are metals or metalloids which include transition metals such as Sb, Fe, Sn, Bi, Al, Ga, In, Ti, Zr, Sc, V, Cr, Mn, Cs; rare earth metals such as the lanthanides Cd, Pr and Nd; and metalloids such as B, P and As. MX n - is a non-basic, non-nucleophilic anion, such as BF 4 -, PF 6 -, AsF 6 -, SbF 6 -, SbCl 6 -, HSO 4 -, ClO 4 -, FeCl 4 =, SnCl 6 - and BiCl 5 =. Bis-diaryl iodonium salts, such as bis(dodecylphenyl) iodonium hexafluoroarsenate and bis(dodecylphenyl) iodonium hexafluoroantimonate and dialkylphenyl iodonium hexafluoroantimonate are preferred. Nitrobenzyl sulfonate esters which are useful as photocleavable acids in the compositions of the present invention have the general formula wherein Z is selected from alkyl groups, aryl groups, alkylaryl groups, halogen substituted alkyl groups, halogen substituted aryl groups, halogen substituted alkylaryl groups, nitro substituted aryl groups, nitro substituted alkylaryl groups, aryl groups having nitro and halogen substituents, alkylaryl groups having nitro and halogen substituents and a group having the formula C 6 H 4 SO 3 CHR'C 6 H 4-m Q m (NO) 2 , R' is selected from hydrogen atom, methyl and nitro substituted aryl groups, each Q is independently selected from hydrocarbon groups, hydrocarbonoxy groups, NO 2 , halogen atoms and organosilicon compounds, m has a value of 0, 1 or 2, with the proviso that Q is not an acidic group. These nitrobenzyl sulfonate photocleavable acids are more completely described in U.K. Application No. 91 24 422.8 filed November 14, 1991. A preferred nitrobenzyl derivative for the process of this invention is where m has a value of 1, Q denotes a NO 2 group in the ortho position in relation to the -CHR'OS(O) 2 Z group and Z denotes a nitrophenyl group, wherein the nitro group is in the para position relative to the sulphonic group or Z denotes a phenylmethyl group or a trifluoropropylmethylphenyl group. It is preferred for purposes of this invention that from 90 to 99.9 weight percent of the random siloxane copolymer be used in the compositions of the invention, and it is highly preferred that from 97 to 99 weight percent be employed, said weight percent being based on the total weight of the composition. The photocleavable acids may be present in any proportions which produce curing in the process of this invention. For purposes of this invention, preferably the amount of photocleavable acid is from 0.1 to 10 percent by weight based on the total weight of the composition, and it is highly preferred to use between 1 and 5 percent by weight based on the total weight of the composition. The present invention further relates to a method of making a curable composition comprising the steps of (I) applying a composition comprising (a) a random siloxane polymer and (b) a photocleavable acid to a solid substrate to form a coating, and (II) exposing the coating to an energy source selected from (i) actinic radiation or (ii) actinic radiation in combination with heat in an amount sufficient to cure the coating. The random siloxane polymer and photocleavable acid are as delineated above. In a preferred embodiment, the solid substrate is a flexible sheet material such as paper, polyolefin film and polyolefin-coated paper or foil. Other suitable solid substrates can be coated by the process of this invention including other cellulosic materials such as wood, cardboard and cotton; metallic materials such as aluminum, copper, steel and silver; siliceous materials such as glass and stone; and synthetic polymer materials such as polyolefins, polyamides, polyesters and polyacrylates. As to form, the solid substrate can be substantially sheet-like, such as a peelable release liner for pressure sensitive adhesive; a fabric or a foil; or substantially three-dimensional in form. Step (II) comprises exposing the coating to an energy source selected from (i) actinic radiation and (ii) actinic radiation in combination with heat in an amount sufficient to cure the coating. By actinic radiation, it is meant ultraviolet light; electron beam radiation; and alpha-, beta-, gamma- and x-rays. By heat, it is meant infrared radiation, hot-air and microwave radiation. Of course, actinic radiation is frequently accompanied by heat and the use of a combination of the two falls within the scope and spirit of the present invention. Herein the term "cure" generally denotes a chemical change which leads the composition going from a liquid to a solid. Curing may be achieved in any of the known ways, including passing a coated substrate under the desired source of radiation, for example a UV lamp, at a predetermined rate, and by exposing a completely coated substrate to radiation by exposure to the required energy source for a predetermined time. In a preferred embodiment of this invention, a flexible sheet material, such as paper, metal foil or tapestock, is coated with a thin coating of the liquid curable composition, preferably in a continuous manner, and the thus coated material is then heated and/or irradiated to rapidly cure the coating, to provide a sheetlike material bearing on at least one surface thereof an adhesive-releasing coating. The adhesive-releasing coating is subsequently brought into contact with a pressure sensitive adhesive, preferably in an in-line manner, to form an article having a peelable, i.e. releasable, adhesive/coating interface. Examples of such an article include, adhesive labels having a peelable backing, adhesive tape in roll form and an adhesive packaged in a strippable container. The pressure sensitive adhesive can be non-silicone-based, such as the well-known acrylic or rubber types or it can be silicone-based, such as the peroxide- or platinum-curable polydiorganosiloxane-based adhesives. The methods and compositions of this invention are also applicable to adhesive materials other than pressure sensitive adhesives. Examples include foods, asphalt and gum polymers. The compositions of this invention are useful as release coatings for pressure sensitive adhesives, as protective coatings and decorative coatings. The compositions prepared in the methods and processes of this invention and the curable coating compositions of this invention can contain any optional components such as photosensitizers, high release additives, reinforcing and extending fillers, hydrocarbons and halohydrocarbons, colorants, dyes, preservatives, fragrances, stabilizers, adhesion modifiers, adhesive-release modifiers and diluents. The method and process of this invention can be completed by mixing the materials described above and any optional components in the order delineated above, using any suitable mixing means, such as a spatula, a drum roller, a mechanical stirrer, a three-roll mill, a sigma blade mixer, a bread dough mixer and a two-roll mill. The coating method can be accomplished by any suitable manner known in the art, such as by spreading, brushing, extruding, spraying, gravure, kiss-roll and air-knife. The following examples are disclosed to further teach the invention which is properly delineated by the appended claims. All amounts (parts and percentages) are by weight unless otherwise indicated. The structures presented in the examples are expressed in mole percents unless otherwise indicated. Cure time for a composition means the time interval required for the composition, when coated onto S2S kraft paper or polypropylene film, at a thickness of 454 grams (1 pound) of silicone per ream of paper or film, to attain the no smear, no migration, no rub-off condition. The no smear condition was determined by lightly streaking the coating with a finger and observing the absence of haze in the streaked area. The no migration condition was determined by firmly adhering a common, pressure sensitive adhesive tape to the coating, removing the tape and folding the removed tape together, adhesive surfaces to each other. Absence of migration of the coating to the tape was indicated by noting that the doubled tape was as difficult to separate as unused tape so doubled. The no rub-off condition was determined by vigorously rubbing the coating with the index finger and noting that the coating could not be removed from the paper. RMS (Root Mean Square - i.e. the square root of the arithmetic mean of the squares of a set of numbers (an average value)) was measured on a high speed peel tester and SAS (Subsequent Adhesive Strength) was measured on a low speed peel tester. Example 1 A 3-neck 100 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 10.95 g (0.0805 moles) MeSi(OMe) 3 , 53.62 g (0.7246 moles) (Me 2 SiO) x , 10.36 g (0.0893 moles) hydroxybutylvinylether and 0.124g potassium silanolate (1500NE (Neutralization Equivalent)). The flask was heated to 130°C. for 4 hours during which time methanol by-product was taken off. After cooling to room temperature, 0.0074 g (0.12 mmoles) glacial acetic acid was added and the mixture stirred 24 hours. The reaction product was filtered through diatomaceous earth and then stripped at 128°C. and 133.3 Pa (1 mm Hg) for 1 hour. The composition recovered had the following average structure Example 2 A 3-neck 100 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 8.87 g (0.0652 moles) MeSi(OMe) 3 , 43.43 g (0.5869 moles) (Me 2 SiO) x , 22.71 g (0.1958 moles) hydroxybutylvinylether and 0.1 g potassium silanolate (1500NE). The flask was heated to 130°C. for 4 hours during which time methanol by-product was taken off. After cooling to room temperature, 0.0060 g (0.10 mmoles) glacial acetic acid was added and the mixture stirred 16 hours. The reaction product was filtered through diatomaceous earth and then stripped at 125°C. and 133.3 Pa (1 mm Hg) for 2 hours. The composition produced had the following average structure Example 3 A 3-neck 100 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 2.09 g (0.0154 moles) MeSi(OMe) 3 , 67.64 g (0.9140 moles) (Me 2 SiO) x , 5.36 g (0.0462 moles) hydroxybutylvinylether and 0.134 g potassium silanolate (1500NE). The flask was heated to 130°C. for 4 hours during which time methanol by-product was taken off. After cooling to room temperature, 0.0080 g (0.134 mmoles) glacial acetic acid was added and the mixture stirred 16 hours. The reaction product was filtered through diatomaceous earth and then stripped at 117°C. and 133.3 Pa (1 mm Hg) for 1 hour. The composition produced had the following average structure Example 4 A 3-neck 100 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 74.03 g (1.0 mole) (Me 2 SiO) x and 2.31 g (0.02 moles) hydroxybutylvinylether. The flask was heated to 130°C. and then 0.14 g potassium silanolate (1500NE) added. Heating was continued for 4 hours. After cooling to room temperature, 0.0085 g (0.14 mmoles) glacial acetic acid was added and the mixture stirred 5 hours. The reaction product was filtered through diatomaceous earth and then stripped at 125°C. and 133.3 Pa (1 mm Hg) for 1 1/2 hours. The composition produced had the following average structure: Me 2 (ViOBuO)SiO(Me 2 SiO) 163 SiMe 2 (OBuOVi) Example 5 A 3-neck 2 liter flask equipped with a thermometer, water condenser, mechanical stirrer and 500 ml dropping funnel was charged with 899.8 g (6.616 moles) MeSi(OMe) 3 and 5.91 g (0.162 moles) concentrated HCl. The flask was heated to 60°C. and then 113.56 g (6.309 moles) H 2 O and 267.98 g (8.37 moles) MeOH added via dropping funnel over the course of 1 hour, maintaining a pot temperature of 65-70°C. by the rate of H 2 O/MeOH addition. After refluxing 3 1/2 hours, the flask was heated to 130°C., allowing 744 g volatiles to be taken off (strongly acidic). The acid number of the product was measured to be 0.2. Next, 2.2 g (0.026 mole) NaHCO 3 and 2.2 g diatomaceous earth were added to the product in the flask and the mixture stirred at room temperature 64 hours. The product was then pressure filtered. Acid number was measured to be less than 0.0002. The composition produced had the following average structure Example 6 A 3-neck 50 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 14.89 g fluid from Example 5, 4.87 g (0.0420 moles) hydroxybutylvinylether and 0.2 g (0.0022 moles) tetraisopropyltitanate. The flask was heated to 85°C. for 4 hours during which time methanol by-product was taken off. The composition produced had the following average structure Example 7 A 3-neck 50 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 14.89 g fluid from Example 5, 7.31 g (0.0630 moles) hydroxybutylvinylether and 0.22 g (0.0024 moles) tetraisopropyltitanate. The flask was heated to 85°C. for 4 hours during which time methanol by-product was taken off. The composition produced had the following average structure Example 8 A 3-neck 50 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 14.89 g fluid from Example 5, 9.76 g (0.0841 moles) hydroxybutylvinylether and 0.25 g (0.0028 moles) tetraisopropyltitanate. The flask was heated to 85°C. for 7 hours during which time methanol by-product was taken off. The composition produced had the following average structure Example 9 A 3-neck 50 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 14.89 g fluid from Example 5, 12.20 g (0.1052 moles) hydroxybutylvinylether and 0.26 g (0.0028 moles) tetraisopropyltitanate. The flask was heated to 85°C. for 14 hours during which time methanol by-product was taken off. The composition produced had the following average structure Example 10 A 3-neck 50 ml flask equipped with a thermometer, magnetic stirrer, short path still and nitrogen purge was charged with 14.89 g fluid from Example 5, 7.31 g (0.0630 moles) hydroxybutylvinylether and 0.21 g (0.0011 moles) barium hydroxide monohydrate. The flask was heated to 85°C. for 5 hours during which time methanol by-product was taken off. Product was then pressure filtered. The composition produced had the following average structure The following examples illustrate the effectiveness of the compositions of the present invention as release coatings. Example 11 The fluid of Example 1 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to 1556 mJ/cm 2 UV light and produced a clear, smooth coating with no rub off and no migration. Example 12 The fluid of Example 2 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to 835 mJ/cm 2 UV light and produced a clear, smooth coating with no rub off and no migration. Example 13 The fluid of Example 6 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to 312 mJ/cm 2 UV light and cured at approximately 38.1 m/min (125 ft/min) using a Fusion UV processor equipped with a 23.6 Watt/mm (600 Watt/inch) H Bulb with no rub off and no migration. Example 14 The fluid of Example 7 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to less than 80 mJ/cm 2 UV light and cured at approximately 114.3 m/min (375 ft/min) using Fusion 23.6 Watt/mm (600 Watt/inch) H Bulb with no rub off and no migration. Coated sheet was clear, smooth, with no odor. Example 15 The fluid of Example 8 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to 96 mJ/cm 2 UV light and cured at approximately 88.4 m/min (290 ft/min) using Fusion 23.6 Watt/mm (600 Watt/inch) H Bulb with no rub off and no migration. Coated sheet was clear, smooth, with no odor. Example 16 The fluid of Example 8 was also evaluated for release against TESA 7475 (acrylic tape) and TESA 7476 (rubber tape) at 10.2 m/min (400 inches per minute). Release was evaluated at two different cure levels, 38.1 m/min (125 ft/min) and 114.3 m/min (375 ft/min). The results are recorded in Table I. Tape Cure speed Release RMS SAS TESA 7475 38.1 m/min 51.9 gf/cm 132.3 83.3 TESA 7475 114.3 m/min 83.5 gf/cm 221.5 87.5 TESA 7476 38.1 m/min 48.0 gf/cm 148.5 54.9 TESA 7476 114.3 m/min 65.4 gf/cm 184.6 48.7 Example 17 The fluid of Example 9 was coated on biaxially orientated polypropylene with 2 wt% bisdodecylphenyl iodonium hexafluoroantimonate catalyst. The coated surface was exposed to less than 88 mJ/cm 2 UV light and cured at approximately 99.1 m/min (325 ft/min) using Fusion 23.6 Watt/mm (600 Watt/inch) H Bulb with no rub off and no migration. Ex.1 Ex.2 Ex. 3 Ex. 4 Ex. 6 Ex. 7 Ex.8 Ex. 9 Ex. 10 Mole Percent w 19.0 23.9 5.0 0.012 21.7 19.5 23.1 15.2 22.4 x 72.2 67.1 93.5 99.988 54 54.3 51.4 50.2 47.4 y 8.89. 0 1.5 0 24.3 26.2 25.5 34.6 30.2 z 0 0 0 0 0 0 0 0 0

Claims: Claims for the following Contracting States : DE, FR, GB A method of making a vinyl ether functional siloxane, the method comprising the steps of: (I) reacting: (a) a silane having the formula R x Si(OR 1 ) 4-x ; (b) water; and (c) an acidic condensation catalyst, wherein R is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent alkyl radical having from 1 to 8 carbon atoms, x has a value of from 0 to 3, with the proviso that the molar ratio of water to alkoxy radicals is less than 0.5; (II) removing alcohol from the reaction mixture of (I) ; (III) neutralizing the mixture of (II) ; (IV) adding a vinyl ether compound having the formula HOR 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms to the mixture of (III) ; (V) adding a transesterification catalyst to the mixture of (IV); and (VI) removing volatiles from the mixture of (V). A method of making a vinyl ether functional siloxane, the method comprising the steps of: (I) reacting in the presence of a non-acidic equilibration catalyst a cyclic compound having the formula with a compound having the formula HOR 6 OCH=CH 2 wherein R 5 is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 6 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms and y has a value of from 3 to 10; (II) removing volatiles from the mixture of (II) ; and (III) neutralizing the mixture of (II). A method according to Claims 1 or 2, further comprising heating the mixture after step (I). A method according to Claim 1, 2 or 3, further comprising adding a polydiorganosiloxane having the formula HOSiR 3 2 (R 3 2 SiO) n OSiR 3 2 OH wherein R 3 is selected from the group consisting of a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms and n has a value of 0 to 15,000, prior to step (III). A method according to Claim 1, further comprising adding an alcohol having the formula R 4 OH, wherein R 4 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, after step (I). A method according to Claim 2, the method further comprising adding a silane having the formula R 8 x Si(OR 9 ) 4-x prior to step (III), wherein R 8 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 9 is a monovalent alkyl radical having from 1 to 8 carbon atoms, x has a value of from 0 to 3. A random siloxane polymer having the general formula: wherein R is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 8 carbon atoms or is a compound having the formula R 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, w has a mole percent of from greater than 0 to 100, x has a mole percent of from 0 to less than 100, y has a mole percent of from 0 to less than 100, z has a mole percent of from 0 to less than 100, a is an integer of from 0 to 3, b is an integer of from 0 to 2, the sum of w+x+y+z being equal to 100 mole percent, with the proviso that at least one R 2 OCH=CH 2 group exists in each molecule, with the exception of those compounds wherein R 2 is a divalent hydrocarbon radical having from 1 to 8 carbon atoms. A copolymer according to Claim 7, the copolymer further comprising a photocleavable acid. A method of making a cured coating composition, the method comprising the steps of: (I) applying a composition to a solid substrate, said composition comprising the random siloxane polymer of Claim 7; and (B) a photocleavable acid, to form a coating; and (II) exposing the coating to an energy source selected from (i) actinic radiation and (ii) actinic radiation in combination with heat in an amount sufficient to cure the coating. A method according to Claim 9, further comprising releasably adhering a pressure sensitive adhesive composition to the cured coating. A method according to Claim 9, wherein the photocleavable acid is an onium salt having its formula selected from R 2 I + MX n - , R 3 S + MX n - , R 3 Se + MX n - , R 4 P + MX n - and R 4 N + MX n - , wherein each R is, independently, an organic radical having from 1 to 30 carbon atoms and MX n - is a non-basic, non-nucleophilic anion. A method according to Claim 11, wherein the non-basic, non-nucleophilic anion is selected from BF 4 -, PF 6 -, AsF 6 -, SbF 6 -, SbCl 6 -, HSO 4 -, ClO 4 -, FeCl 4 =, SnCl 6 - and BiCl 5 =. A method according to Claim 11, wherein the onium salt is selected from bis(dodecylphenyl) iodonium hexafluoroarsenate, bis (dodecylphenyl) iodonium hexafluoroantimonate and dialkylphenyl iodonium hexafluoroantimonate. A method according to Claim 11, wherein the photocleavable acid is a nitrobenzyl sulfonate ester having the general formula wherein Z is selected from alkyl groups, aryl groups, alkylaryl groups, halogen substituted alkyl groups, halogen substituted aryl groups, halogen substituted alkylaryl groups, nitro substituted aryl groups, nitro substituted alkylaryl groups, aryl groups having nitro and halogen substituents, alkylaryl groups having nitro and halogen substituents and a group having the formula C 6 H 4 SO 3 CHR'C 6 H 4-m Q m (NO) 2 , R' is selected from hydrogen atom, methyl and nitro substituted aryl groups, each Q is independently selected from hydrocarbon groups, hydrocarbonoxy groups, NO 2 , halogen atoms and organosilicon compounds, m has a value of 0, 1 or 2, with the proviso that Q is not an acidic group. A method according to Claim 9, wherein the substrate is selected from paper or plastic film. Claims for the following Contracting State : NL A method of making a vinyl ether functional siloxane, the method comprising the steps of: (I) reacting: (a) a silane having the formula R x Si(OR 1 ) 4-x ; (b) water; and (c) an acidic condensation catalyst, wherein R is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent alkyl radical having from 1 to 8 carbon atoms, x has a value of from 0 to 3, with the proviso that the molar ratio of water to alkoxy radicals is less than 0.5; (II) removing alcohol from the reaction mixture of (I) ; (III) neutralizing the mixture of (II) ; (IV) adding a vinyl ether compound having the formula HOR 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms to the mixture of (III) ; (V) adding a transesterification catalyst to the mixture of (IV); and (VI) removing volatiles from the mixture of (V). A method of making a vinyl ether functional siloxane, the method comprising the steps of: (I) reacting in the presence of a non-acidic equilibration catalyst a cyclic compound having the formula with a compound having the formula HOR 6 OCH=CH 2 wherein R 5 is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 6 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms and y has a value of from 3 to 10; (II) removing volatiles from the mixture of (I); and (III) neutralizing the mixture of (II). A method according to Claims 1 or 2, further comprising heating the mixture after step (I). A method according to Claim 1, 2 or 3, further comprising adding a polydiorganosiloxane having the formula HOSiR 3 2 (R 3 2 SiO) n OSiR 3 2 OH wherein R 3 is selected from the group consisting of a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms and n has a value of 0 to 15,000, prior to step (III). A method according to Claim 1, further comprising adding an alcohol having the formula R 4 OH, wherein R 4 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, after step (I). A method according to Claim 2, the method further comprising adding a silane having the formula R 8 x Si(OR 9 ) 4-x prior to step (III), wherein R 8 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, R 9 is a monovalent alkyl radical having from 1 to 8 carbon atoms, x has a value of from 0 to 3. A random siloxane polymer having the general formula: wherein R is a monovalent hydrocarbon radical or halohydrocarbon radical having from 1 to 20 carbon atoms, R 1 is a monovalent hydrocarbon or halohydrocarbon radical having from 1 to 8 carbon atoms or is a group having the formula R 2 OCH=CH 2 wherein R 2 is a divalent hydrocarbon or halohydrocarbon radical having from 1 to 20 carbon atoms, w has a mole percent of from greater than 0 to 100, x has a mole percent of from 0 to less than 100, y has a mole percent of from 0 to less than 100, z has a mole percent of from 0 to less than 100, a is an integer of from 0 to 3, b is an integer of from 0 to 2, the sum of w+x+y+z being equal to 100 mole percent, with the proviso that at least one R 2 OCH=CH 2 group exists in each molecule. A copolymer according to Claim 7, the copolymer further comprising a photocleavable acid. A method of making a cured coating composition, the method comprising the steps of: (I) applying a composition to a solid substrate, said composition comprising (A) the random siloxane polymer of Claim 7; and (B) a photocleavable acid, to form a coating; and (II) exposing the coating to an energy source selected from (i) actinic radiation and (ii) actinic radiation in combination with heat in an amount sufficient to cure the coating. A method according to Claim 9, further comprising releasably adhering a pressure sensitive adhesive composition to the cured coating. A method according to Claim 9, wherein the photocleavable acid is an onium salt having its formula selected from R 2 I + MX n - , R 3 S + MX n - , R 3 Se + MX n - , R 4 P + MX n - and R 4 N + MX n - , wherein each R is, independently, an organic radical having from 1 to 30 carbon atoms and MX n - is a non-basic, non-nucleophilic anion. A method according to Claim 11, wherein the non-basic, non-nucleophilic anion is selected from BF 4 -, PF 6 -, AsF 6 -, SbF 6 -, SbCl 6 -, HSO 4 -, ClO 4 -, FeCl 4 =, SnCl 6 - and BiCl 5 =· A method according to Claim 11, wherein the onium salt is selected from bis(dodecylphenyl) iodonium hexafluoroarsenate, bis (dodecylphenyl) iodonium hexafluoroantimonate and dialkylphenyl iodonium hexafluoroantimonate. A method according to Claim 11, wherein the photocleavable acid is a nitrobenzyl sulfonate ester having the general formula wherein Z is selected from alkyl groups, aryl groups, alkylaryl groups, halogen substituted alkyl groups, halogen substituted aryl groups, halogen substituted alkylaryl groups, nitro substituted aryl groups, nitro substituted alkylaryl groups, aryl groups having nitro and halogen substituents, alkylaryl groups having nitro and halogen substituents and a group having the formula C 6 H 4 SO 3 CHR'C 6 H 4-m Q m (NO) 2 , R' is selected from hydrogen atom, methyl and nitro substituted aryl groups, each Q is independently selected from hydrocarbon groups, hydrocarbonoxy groups, NO 2 , halogen atoms and organosilicon groups, m has a value of 0, 1 or 2, with the proviso that Q is not an acidic group. A method according to Claim 9, wherein the substrate is selected from paper or plastic film.

Inventors: BUJANOWSKI VALERIE JOY, GLOVER SHEDRIC ONEAL, HOMAN GARY REX, PERZ SUSAN VICTORIA, SKINNER MICHAEL WARD, ZIEMELIS JAZEPS MARIS, BUJANOWSKI, VALERIE JOY, GLOVER, SHEDRIC ONEAL, HOMAN, GARY REX, PERZ, SUSAN VICTORIA, SKINNER, MICHAEL WARD, ZIEMELIS, JAZEPS MARIS
Applicants: DOW CORNING, DOW CORNING CORPORATION
Application year: 1994
Main classification: C08G77
IPC codes: C08G77, C09D183, C08K5, C08L83, C08F2